I've been known to un-quilt an entire queen sized quilt and re-quilt it-- but that was a salvageable project. Since I also like to experiment, I would probably have done as you did, try to scape what glue off I can. If I couldn't get the glue off, then I'd use the gluey piece in an experimental way just to see what happens. I have also been known to cut "unredeemable" quilts into long strips and stitch them together with other strips from "unredeemable" quilts to make art pieces that I then embellish with stitching, felting, applied ribbons, etc. Sometimes they turn out to be pretty interesting pieces of art. Other times, they just become fodder for the next time I want to cut something up and see what happens if I layer it with something else I cut up. I can keep myself entertained for hours doing those kinds of things. They don't necessarily lead to something useable, but I usually have fun playing with them.
Rob